Wittmer J P, Meyer H, Baschnagel J, Johner A, Obukhov S, Mattioni L, Müller M, Semenov A N
Institut Charles Sadron, 6 Rue Boussingault, 67083 Strasbourg, France.
Phys Rev Lett. 2004 Oct 1;93(14):147801. doi: 10.1103/PhysRevLett.93.147801. Epub 2004 Sep 29.
The scaling of the bond-bond correlation function P1(s) along linear polymer chains is investigated with respect to the curvilinear distance s along the flexible chain and the monomer density rho via Monte Carlo and molecular dynamics simulations. Surprisingly, the correlations in dense three-dimensional solutions are found to decay with a power law P1(s) approximately s(-omega) with omega=3/2 and the exponential behavior commonly assumed is clearly ruled out for long chains. In semidilute solutions, the density dependent scaling of P1(s) approximately g(-omega(0))(s/g)(-omega) with omega(0)=2-2nu=0.824 (nu=0.588 being Flory's exponent) is set by the number of monomers g(rho) in an excluded volume blob. Our computational findings compare well with simple scaling arguments and perturbation calculation. The power-law behavior is due to self-interactions of chains caused by the chain connectivity and the incompressibility of the melt.
通过蒙特卡罗模拟和分子动力学模拟，研究了沿线性聚合物链的键-键关联函数P1(s)相对于沿柔性链的曲线距离s和单体密度ρ的标度关系。令人惊讶的是，发现在致密三维溶液中的关联以幂律P1(s)∼s^(-ω)衰减，其中ω = 3/2，对于长链，通常假设的指数行为显然被排除。在半稀溶液中，P1(s)的密度依赖标度为P1(s)∼g^(-ω(0))(s/g)^(-ω)，其中ω(0)=2 - 2ν = 0.824（ν = 0.588为弗洛里指数），由排除体积团块中的单体数g(ρ)决定。我们的计算结果与简单的标度论证和微扰计算结果吻合得很好。幂律行为是由于链连接性和熔体不可压缩性导致的链的自相互作用。
